USPTO Patents Application 10687850

(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(19) World Intellectual Property Organization

International Bureau

(43) International Publication Date (10) International Publication Number

21 February 2002 (21.02.2002) PCT WO 02/13970 A2

(51) International Patent Classification 7 :

(21) International Application Number: PCT/US01/23531

(22) International Filing Date: 26 July 2001 (26.07.2001)
(25) Filing Language: English

BOIL 3/00 (81) Designated States (national): AE, AG, AL, AM, AT, AU,
AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU,
CZ, DE, DK, DM, DZ, EC, EE, ES, FI, GB, GD, GB, GH,
GM, HR, HU, [D, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC,
LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW,
MX, MZ, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK,
SL, TJ, ™, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW.

(26) Publication Language:

English

(30) Priority Data:

09/637,504

1 1 August 2000 ( 1 1 .08.2000) US

(71) Applicant: LIFESCAN, INC. [US/US]; 1000 Gibraltar
Drive, Milpitas, CA 95035-6312 (US).

(72) Inventors: HOUSE, Alien; 421 Sutton Circle, Danville,
CA 94506 (US). OLSON, Lorin; 1230 Ml Hermon Road,
Scotts Valley, CA 95066 (US).

(74) Agent: FIELD, Bret, E.; Bo zicevic, Field & Francis, LLP,
Suite 200, 200 Middlefield Road, Menlo Park, CA 94025
(US).

(84) Designated States (regional): ARIPO patent (GH, GM,
KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), Eurasian
patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European
patent (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE,
IT, LU, MC, NL, PT, SE, TR), OAPI patent (BF, BJ, CF,
CG, CI, CM, GA, GN, GQ, GW, ML, MR, NE, SN, TD,
TG).

Published:

— without international search report and to be republished
upon receipt of that report

For two-letter codes and other abbreviations, refer to the "Guid-
ance Notes on Codes and Abbreviations" appearing at the begin-
ning of each regular issue of the PCT Gazette.

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(54) Title: GIMBALED BLADDER ACTUATOR FOR USE WITH TEST STRIPS

(57) Abstract: Gimbaled bladder actuators and methods for their use in compressing bladders present on test strips are provided.
The subject actuators are characterized by the presence of a gimbaled compression pad under movement control of an actuating
means, preferably an automated actuating means. Also provided are meters for reading test strips that include bladders, where the
meters include the subject gimbaled bladder actuators.

WO 02/13970 PCT/US01/23531
GBMBALED BLADDER ACTUATOR FOR USE WITH TEST STRIPS

PRODUCTION

Field of the Invention

5 The field of this invention is fluidic medical diagnostic devices for measuring the

concentration of an analyte in or a property of a biological fluid.

Background of the Invention

A variety of medical diagnostic procedures involve tests on biological fluids, such as

1 0 blood, urine, or saliva, and are based on a change in a physical characteristic of such a fluid or
an element of the fluid, such as blood serum. The characteristic can be an electrical, magnetic,
fluidic, or optical properly. When an optical property is monitored, these procedures may make
use of a transparent or translucent device to contain the biological fluid and a reagent A
change in light absorption of the fluid can be related to an analyte concentration in, or property

15 of; the fluid.

In many such devices, fluid is introduced into the device at one location but analyzed at
another. In such devices, movement of the introduced fluid from the introduction location to the
measurement location is necessary. As such, these devices require a means for moving fluid
from the introduction site to the measurement site.

20 A variety of different design configurations have been developed to provide for this

fluid movement One type of device relies on capillary action to move fluid through the device,
where the fluid paths through the device are dimensioned to provide for this capillary action.
Other designs include those intended for use with gravity, those intended for use with inj ection
of the sample under pressure, and the like.

25 In one class of fluidic test devices or strips that find use in various assay applications,

fluid is moved through the device from the point of introduction by negative pressure, where
the negative pressure is typically provided by a compressible bladder. Such devices include
those described in U.S. Patent 3,620,676; U.S. Patent 3,640,267 and EP 0 803 288.

With these types of devices, there is a need to be able to actuate the bladder in a .

3 0 reproducible and uniform manner, such that errors in the assay are not introduced through
variations in bladder volume through the compression and decompression cycle.

1

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Relevant Literature

References of interest include: U.S. PatentNos.: 3,620,676; 3,640,267; 4,088,448;
4,426,451; 4,868,129; 5,104,813; 5,230,866; 5,700,695; 5,736,404; 5,208,163; and European
Patent Application EP 0 803 288.

5

SUMMARY OF THE INVENTION
Gimbaled bladder actuators and methods for their use in compressing bladders
present on fluidic devices or test strips are provided. The actuators are characterized by the
presence of a gimbaled compression pad under movement control of an actuating means,
10 preferably an automated actuating means. Also provided are meters for reading test strips
that include bladders, where the meters include the subject gimbaled bladder actuators.

BRIEF DESCRIPTION OF THE FIGURES
Fig. 1 is a plan view of a test strip which includes a bladder that may be actuated by the
1 5 subject gimbaled bladder actuators.

Fig. 2 is an exploded view of the device of Fig. 1 . .
Fig. 3 is a perspective view of the device of Fig. 1.

Fig. 4 is a schematic of a meter that includes a gimbaled bladder actuator according to
the subject invention.

20 Fig. 4A depicts an alternative embodiment of an element of the meter of Fig. 4.

Fig. 5 is a graph of data that is used to determine PT time.

Fig. 6 A provides a top view of a gimbaled bladder actuator according to the subj ect
invention, and Fig. 6B shows a side view of the device shown in Fig. 6 A.

Figs 7A and 7B provide top and bottom perspective views of the device shown in
25 Figs. 6 A and 6B.

Fig. 8 A provides a top perspective view of the device shown in Fig. 6A, while Fig.
8B provides a view along line B-B of Fig. 8 A and Fig. 8C provides a blow-up view of Fig.
8B.

30 DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Gimbaled bladder actuators and methods for their use in compressing bladders present
on test strips are provided. The subject actuators are characterized by the presence of a
gimbaled compression pad under movement control of an actuating means, preferably an

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automated actuating means. Also provided are meters for reading bladder including test
strips, where the meters include the subject gimbaled bladder actuating devices. In further
describing the subject invention, the subject gimbaled bladder actuators are described first in
greater detail, followed by a description of the test strip/meter systems with which the
5 subject gimbaled bladder actuator find use, as well as methods for using the same.

Before the subject invention is described further, it is to be understood that the
invention is not limited to the particular embodiments of the invention described below, as
variations of the particular embodiments may be made and still fall within the scope of the
10 appended claims. It is also to be understood that the terminology employed is for the

purpose of describing particular embodiments, and is not intended to be limiting. Instead,
the scope of the present invention will be established by the appended claims.

In this specification and the appended claims, singular references include the plural,
15 unless the context clearly dictates otherwise. Unless defined otherwise, all technical and
scientific terms used herein have the same meaning as commonly understood to one of
ordinary skill in the art to which this invention belongs.

Gimbaled bladder Actuators
20 As summarized above, the subject invention provides bladder compressing devices

or actuators that find use in compressing bladders on fiuidic devices or test strips that include
bladders. Li further describing the subject devices, the subject bladder actuators will be
described first in general terms, followed by a detailed discussion of a representative actuator
in terms of the figures.

25 A feature of the subj ect bladder compressing devices or actuators is that they include

a gimbaled compression pad. As such, the subject bladder actuators are gimbaled bladder
actuators. By gimbaled compression pad is meant a planar compression element that is
suspended from a holder in a manner such that the planar compression element becomes
parallel to the surface it contacts during actuation. By planar compression element is meant a

30 . rigid piece having a substantially planar surface. The view normal to the planar surface of
this element may have varying area configurations, including circular, square, rectangular,
trapezoidal, oval, triangular, irregular, etc., and in many embodiments is selected so as to
contact substantially all of the upper surface of a bladder of a test strip or fiuidic device with

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which the gimbaled bladder actuator is employed. The actual area of the planar surface may
vary, but is generally at least about 0.008 square inches ? usually at least about 0.15 square
inches and more usually at least about 0.2 square inches, where the actual area may be as
great as 0.4 square inches or greater, but generally does not exceed about 0.6 square inches
5 and usually does not exceed about 0.8 square inches. In certain embodiments, the actual area
ranges from about 0.15 to 0.25 square inches, usually from about 0.19 to 0.21 square inches.

The gimbaled compression pad is characterized by being capable of applying
uniform pressure to the bladder upon actuation. By uniform pressure is meant that the
pressure applied by the planar compression element at any two different locations on the

10 bladder that is contacted by the compression element is substantially the same or identical.
Where there is pressure variance, the magnitude of the variance at any two given locations
typically does not exceed about 18 lbs per square inch, usually does not exceed about 7 lbs
per square inch and more usually does not exceed about 2 lbs per square inches. The amount
of force applied by the gimbaled pad to the bladder during use typically ranges in many

15 embodiments from about 0.25 to 10, usually from about 0.5 to 5 and more usually from
about 1.0 to 1.5 lbs.

Also present in the subject bladder compressing devices is an actuating means for
actuating or moving the gimbaled compression pad onto and off of a bladder of present on a
test strip. In principal, any convenient actuating means may be employed that is capable of

20 contacting the gimbaled compression pad against the bladder surface in a manner that

applies substantially uniform pressure across the bladder surface, as described supra. Thus,
the actuation means may be manual or automatic. Manual actuation means may simply be a
compression button that can be pushed by an operator to achieve contact of the gimbaled
compression pad and the bladder surface. In many preferred embodiments, the actuation

25 means is an automated actuation means that is capable of contacting the bladder surface with
the gimbaled compression pad in a reproducible manner.

While any convenient automated actuation means may be employed, one convenient
automated actuation means includes the following elements: CO a lever arm; (Li) a chassis;
and (iii) a solenoid. In this representative automated actuation means, at one end of the lever

30 arm the gimbaled compression pad (i.e. the planar compression element and the holder) is
attached. The lever arm is such that it is capable of holding the gimbaled compression pad
over the bladder such that, upon actuation, the gimbaled compression pad contacts the
bladder in a manner sufficient to compress the bladder, as described supra. The other end of

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the lever arm is connected to a chassis or analogous element. The length of the lever arm
generally ranges from about 0.3 inches to 0.4 inches, usually from about 0.345 inches to
0.355 inches.

The chassis or analogous element provides for operative communication between the
5 lever arm and the solenoid. The chassis may have any convenient configuration, where a
representative configuration is provided in the figures, described infra.

Connected to the chassis is a solenoid actuator which is capable of moving the lever
arm and therefore the gimbaled compression pad in the desired manner upon actuation. The
solenoid is generally a dual action solenoid capable of moving the gimbaled compression

10 pad in two directions: a first direction onto the bladder and a second direction off of the
bladder. Generally, the solenoid is under the control of a solenoid actuation means, where
the means may be manual (i.e. may actuate the solenoid following direct input from a human
user) or automated (i.e. may automatically actuate the solenoid following detection of an
event by a sensor in a device, such as a sample placement detecting sensor).

1 5 Turning now to the figures, Fig. 6 A provides a top view of a bladder compression

device 62 of the subject invention positioned over a test strip 64 that includes a bladder. Fig.
6B shows a side view of the device shown in Fig. 6A. In Fig. 6B, bladder compression
device is seen placed over the end of test strip 64. Bladder compression device 62 includes
solenoid actuation means 66 and lever arm 68. Located on lever arm 68 is gimbaled

20. compression pad 69, which is placed above bladder 63 of test strip 64.

Fig, 7 A and Fig. 7B provide top and bottom perspective views of the device shown
in Figs. 6A and 6B. Gimbaled compression pad 69 can be seen in Fig. 7A.

Fig. 8 A provides atop perspective view of the device shown in Fig. 6A. In Fig. 8 A,
bladder compression device 62 is positioned over test strip 64. The top of solenoid 66 and

25 lever arm 68 is visible, as well as gimbaled compression pad 69. Also visible is sample
application region 65 of test strip 64. Fig. 8B provides a blow up view along line B-B
showing gimbaled compression pad 69. Gimbaled compression pad 69 is made up of planar
compression element 69a in holder 69b. Fig. 8C provides a blow-up view of Fig. 8A,
showing gimbaled compression pad 69 positioned over test strip 64.

30

Systems

The above described gimbaled bladder compressing devices or actuators find use in
systems made up of test strips and meters, as described in greater detail below.

5

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Test Strips.

The test strips with which the subject gimbaled bladder actuators find use are fluidic
devices that generally include a sample application area; a bladder, to create a suction force to
draw the sample into the device; a measurement area, in which the sample may undergo a
5 change in an optical parameter, such as light scattering; and a stop junction to precisely stop
flow after filling the measurement area. Preferably, the test strip is substantially transparent over
the measurement area, so that the area can be illuminated by a light source on one side and the
transmitted light measured on the opposite side.

A representative test strip with which the subject gimbaled bladder actuators find use is

1 0 shown in Figs. 1, 2 and 3 . Fig. 1 provides a plan view of representative device 10 , while Fig. 2
provides an exploded view and Fig. 3 provides a perspective view of the same representative
device. Sample is applied to sample port 12 after bladder 14 has been compressed. Clearly, the
region of layer 26 and/or layer 28 that adjoins the cutout for bladder 14 must be resilient, to
permit bladder 14 to be compressed. Polyester of about 0. 1 mm thickness has suitable

1 5 resilience and springiness. Preferably, top layer 26 has a thickness of about 0. 125 mm, bottom
layer 28 about 0.100 mm. When the bladder is released, suction draws sample through channel
16 to measurement area 1 8, which preferably contains a reagent 20. In order to ensure that
; measurement area 1 8 can be filled with sample, the volume of bladder 14 is preferably at least
about equal to the combined volume of channel 16 and measurement area 1 8. If measurement

20 area 1 8 is to be illuminated from below, layer 28 must be transparent where it adjoins
measurement area 1 8.

As shown in Figs. 1, 2, and 3, stop junction 22 adjoins bladder 14 and measurement
area 18; however, a continuation of channel 16 may be on either or both sides of stop junction
22, separating the stop junction from measurement area 1 8 and/or bladder 14. When the sample

25 reaches stop junction 22, sample flow stops. The principle of operation of stop junctions is
described in U.S. Patent 5,230,866, incorporated herein by reference.

As shown in Fig. 2, all the above elements are formed by cutouts in intermediate layer
24, sandwiched between top layer 26 and bottom layer 28. Preferably, layer 24 is double-sided
adhesive tape. Stop junction 22 is formed by an additional cutout in layer 26 and/or 28, aligned

30 with the cutout in layer 24 and sealed with seating layer 30 and/or 32. Preferably, as shown, the
stop junction comprises cutouts in both layers 26 and 28, with sealing layers 30 and 32. Each
cutout for stop junction 22 is at least as wide as channel 16. Also shown in Fig. 2 is an optional
filter 12A to cover sample port 12. The filter may separate out red blood cells from a whole

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blood sample and/or may contain a reagent to interact with the blood to provide additional
information. A suitable filter comprises an anisotropic membrane, preferably a polysulfone
membrane of the type available from Spectral Diagnostics, Inc., Toronto, Canada Optional
reflector 18A may be on, or adjacent to, a surface of layer 26 and positioned over measurement
5 area 18. If the reflector is present, the device becomes a transflectance device.

The test strip pictured in Fig. 2 and described above is preferably formed by laminating
thermoplastic sheets 26 and 28 to a thermoplastic intermediate layer 24 that has adhesive on
both of its surfaces. The cutouts that form the elements shown in Fig. 1 may be formed, for
example, by laser- or die-cutting of layers 24, 26, and 28. Alternatively, the device can be

1 0 formed of molded plastic. Preferably, the surface of sheet 28 is hydrophilic. (Film 9962,
available from 3M, St. Paul, MN.) However, the surfaces do not need to be hydrophilic,
because the sample fluid will fill the device without capillary forces. Thus, sheets 26 and 28
may be untreated polyester or other thermoplastic sheet, well known in the art Similarly, since
gravity is not involved in filling, the device can be used in any orientation. Unlike capillary fill

1 5 devices that have vent holes through which sample could leak, these types of devices vent
through the sample port before sample is applied, which means that the part of the strip that is
first inserted into the meter is without an opening, reducing the risk of contamination.

Other fluidic device configurations are also possible, where such alternative device
configurations include those that have: (a) a bypass channel; (b) multiple parallel measurement

20 areas; and/or (c) multiple in series measurement areas; etc. In addition, the above described
laminated structures can be adapted to injection molded structures. A variety of alternative
fluidic devices with which the subject gimbaled bladder compressing devices may find use are
described in co-pending application serial nos. 09/333765, filed June 15, 1999; and 09/356248,
filed July 16, 1999, the disclosures of which are herein incorporated by reference.

25

Meters

The subject gimbaled bladder actuators find use in meters, generally automated meters,
that are designed for use with the above described test strips. A representative meter is depicted
in Fig. 4, where a representative test strip 10 is inserted into the meter. The meter shown in Fig.
30 4 includes strip detector 40 (made up of LED 40a and detector 40b), sample detector 42 (made
up of light source 42a and detector 42b), measurement system 44 (made up of LED 44a and
detector 44b), and optional heater 46. The device further includes a gimbaled bladder actuator
48, which is described in greater detail supra. The gimbaled bladder actuator is, in many

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embodiments, actuated by the strip detector 40 and the sample detector 42, such that when a
strip is inserted into the meter and detected by the strip detector, the gimbaled bladder actuator
is depressed, and when the sample is added to the fluidic device or strip inserted into the meter,
the gimbaled bladder actuator is withdrawn so as to decompress the bladder and concomitantly
5 pull sample into the measurement area of the device via the resultant negative pressure
conditions in the fluid channels) of the test strip. Also present is a meter display 50 that
provides for an interface with the user.

Methods of Use

1 0 The above described test strip/meter systems that include the subject gimbaled

bladder actuators are suitable for use in a variety of analytical tests of biological fluids, such
as determining biochemical or hematological characteristics, or measuring the concentration
in such fluids of analytes such as proteins, hormones, carbohydrates, lipids, drugs, toxins,
gases, electrolytes, etc. The procedures for performing these tests have been described in the

15 literature. Among the tests, and where they are described, are the following: (1)

Chromogenic Factor Xlla Assay (and other clotting factors as well): Rand, M.D. et aL,
Blood, 88,3432 (1996); (2) Factor X Assay: Bick, R.L. Disorders of Thrombosis and
Hemostasis: Clinical and Laboratory Practice. Chicago, ASCP Press, 1992.; (3) DRWT
(Dilute Russells Viper Venom Test): Exner, T. et al, Blood Coag. FibrinoL, 1> 259 (1990); (4)

20 Immunonephelometric and Immunotuibidimetric Assays for Proteins: Whicher, J.T., CRC
Crit Rev. Clin Lab Sci. 18:213 (1983); (5) TPA Assay: Mann, KG, et aL, Blood, 76, 755,
(1990).; and Hartshorn, JK etal 9 Blood, 78, 833 (1991); (6) APTT (Activated Partial
Thromboplastin Time Assay): Proctor, RR and Rapaport, S.I Amer. J. Clin. Path, 36, 212
(1961); Brandt, IT. and Tripled; DA Amer. J. Clin. Path., 76, 530 (1981); and Kelsey, Pit

25 Thromb. Haemost 52, 172 (1984); (7)HbAlc Assay (Glycosylated Hemoglobin Assay): Nicol,
D.J. et al., Clin. Chem. 29, 1694 (1983); (8) Total Hemoglobin: Schneck etai, Clinical Chem.,
32/33. 526 (1986); and U.S. Patent 4,088,448; (9) Factor Xa: Vinazzer, H., Proc. Symp.
Dtsch. Ges. Klin. Chem., 203 (1977), ed. By Witt, IJ\Q) Colorimetric Assay for Nitric
Oxide: Schmidt, EH, et al, Biochemica, 2, 22 (1995).

30 The above described test strip/meter systems are particularly well suited for measuring

blood-clotting time - "prothrombin time" or "PT time, " as more folly described in Application
Serial Nos. 09/333765, filed June 15, 1999; and 09/356248, filed July 16, 1999; the disclosures

8

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of which are herein incorporated by reference. The modifications needed to adapt the device for
applications such as those listed above require no more than routine experimentation.

In using the above systems that include the subject gimbaled bladder actuator, the first
step the user performs is to turn on the meter, thereby energizing strip detector 40, sample
5 detector 42, measurement system 44, and optional heater 46. The second step is to insert the
strip. Preferably, the strip is not transparent over at least a part of its area, so that an inserted
strip will block the illumination by LED 40a of detector 40b , (More preferably, the
intermediate layer is formed of a non-transparent material, so that background light does not
enter measurement system 44.) Detector 40b thereby senses that a strip has been inserted and

10 triggers gimbaled bladder actuator 48 to compress bladder 14. A meter display 50 then directs
the user to apply a sample to sample port 12 as the third and last step the user must perform to
initiate the measurement sequence. The empty sample port is reflective. When a sample is
introduced into the sample port, it absorbs light from LED 42a and thereby reduces the light
that is reflected to detector 42b. That reduction in light, in turn, signals gimbaled bladder

1 5 actuator 48 to release bladder 14. The resultant suction in channel 1 6 draws sample through
measurement area 1 8 to stop junction 22. Light from LED 44a passes through measurement
area 18, and detector 44b monitors the light transmitted through the sample as it is clotting.
Analysis of the transmitted light as a function of time (as described below) permits a calculation
of the PT time, which is displayed on the meter display 50. Preferably, sample temperature is

20 maintained at about 3 9°C by heater 46.

As described above, the detector senses a sample in sample port 12, simply by detecting
a reduction in (specular) reflection of a light signal that is emitted by 42a and detected by 42b.
However, that simple system cannot easily distinguish between a whole blood sample and some
other liquid (e.g., blood serum) placed in the sample port in error or, even, an object (e.g., a

25 finger) that can approach sample port 1 2 and cause the system to erroneously conclude that a
proper sample has been applied. To avoid this type of error, another embodiment measures
diffuse reflection from the sample port. This embodiment appears in Fig. 4A, which shows
detector 42b positioned normal to the plane of strip 10. With the arrangement shown in Fig.
4A, if a whole blood sample has been applied to sample port 12, the signal detected by 42b

3 0 increases abruptly, because of scattering in the blood sample, then decreases, because of

rouleaux formation . The detector system 42 is thus programmed to require that type of signal
before causing gimbaled bladder actuator 48 to release bladder 14. The delay of several
seconds in releasing bladder 14 does not substantially affect the readings described below

WO 02/13970 PCT7US01/23531

Fig. 5 depicts a typical "clot signature" curve in which the current from detector 44b is
plotted as a function of time. Blood is first detected in the measurement area by 44b at time 1 .
In the time interval A, between points 1 and 2, the blood fills the measurement area. The
reduction in current during that time interval is due to light scattered by red cells and is thus an
5 approximate measure of the hematocrit At point 2, sample has filled the measurement area and
is at rest, its movement having been stopped by the stop junction. The red cells begin to stack
up like coins (rouleaux formation). The rouleaux effect allows increasing light transmission
through the sample (and less scattering) in the time interval between points 2 and 3. At point 3,
clot formation ends rouleaux formation and transmission through the sample reaches a
10 maximum. The FT time can be calculated from the interval B between points 1 and 3 or
between 2 and 3. Thereafter, blood changes state from liquid to a semi-solid gel, with a
corresponding reduction in light transmission. The reduction in current C between the
maximum 3 and endpoint 4 correlates with fibrinogen in the sample.

It is evident from the above results and discussion that the subject invention provides
a means for applying uniform and reproducible bladder compression and decompression in
test strips that include bladders. As such, the subject devices provide for the elimination of a
source of error in analytical assays using such test strips. As such, the subject invention
represents a significant contribution to the art.

All publications and patents cited in this specification are herein incorporated by
reference as if each individual publication or patent were specifically and individually
indicated to be incorporated by reference. The citation of any publication is for its disclosure
prior to the filing date and should not be construed as an admission that the present invention
is not entitled to antedate such publication by virtue of prior invention.

Although the foregoing invention has been described in some detail by way of
illustration and example for purposes of clarity of understanding, it is readily apparent to
those of ordinary skill in the art in light of the teachings of this invention that certain changes
30 and modifications may be made thereto without departing from the spirit or scope of the
appended claims.

15

20

25

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1 . A gimbaled bladder actuator, said actuator comprising:
a gimbaled compression pad; and

5 actuating means for contacting said gimbaled compression pad with a bladder in a

manner sufficient to compress said bladder.

2. The gimbaled bladder actuator according to Claim 1, wherein said actuating means
comprises a lever arm under the control of an automatic movement means.

10

3 . The gimbaled bladder actuator according to Claim 2, wherein said automatic
movement means comprises a solenoid.

4. The gimbaled bladder actuator according to Claims 2 or 3, wherein said lever arm is
1 5 attached to said movement means by a chassis.

5. The gimbaled bladder actuator according to Claims 1 to 4, wherein said gimbaled
compression pad has an actual area ranging from about 0.19 square inches to 0.21 square
inches.

20

6. The gimbaled bladder actuator according to Claims 2 to 5, wherein said arm moves
said gimbaled compression pad against a bladder in a manner sufficient to apply uniform
pressure to said bladder.

25 7 . The gimbaled bladder actuator according to any of the preceding claims, wherein said
gimbaled compression pad is capable of placing a compressive force on a bladder ranging
from about 1 lb to 1.5 lb.

8. An automatic meter for reading a test strip, said meter comprising:
30 a gimbaled bladder actuator according to any of the preceding claims.

11

WO 02/13970 PCT7US01/23531

9. A method of moving sample fluid in a test strip that includes a bladder, said method
comprising:

(a) positioning a bladder of said test strip in operative relationship with a
gimbaled bladder actuator, wherein said gimbaled bladder actuator is an actuator

5 according to any one of Claims 1 to 7;

(b) actuating said actuating means in a manner sufficient to compress said
bladder;

(c) applying said sample fluid to a sample receiving region of said test strip; and

(d) actuating said actuating means in a manner sufficient to decompress said
10 bladder and thereby move said sample fluid in said test strip;

whereby said sample .fluid is moved in said test strip.

10. The method according to Claim 9, wherein said gimbaled bladder actuator is a
component of a meter and said method further comprises introducing said test strip into said

15 meter.

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FIG. 1

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2/9

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3/9

FIG. 3

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5/9

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6/9

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7/9

FIG. 7A

FIG. 7B

■4 w

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8/9

FIG. 8A

SEE DETAIL B

FIG. 8B

SECTION B"B

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9/9